KR101387530B1 - Method of resouce allocation for HARQ - Google Patents

Abstract

The present invention relates to a resource allocation method for an automatic retransmission request. A resource allocation method for requesting automatic retransmission includes transmitting a MAP message including information on whether to support differential allocation, storing MAP information included in the MAP message for a predetermined frame, and acknowledging the predetermined frame. If the negative message is received, the method may include transmitting sub burst information including differential allocation information for the sub burst to be retransmitted. The present invention can improve the performance of the system by reducing the MAP overhead associated with HARQ through a method of transmitting only a difference based on MAP information of an initial MAP message when retransmitting HARQ subbursts when there is a lot of HARQ traffic.

HARQ, Differential Allocation, MAP Message, Burst

Description

Resource allocation method for automatic retransmission request {Method of resouce allocation for HARQ}

The present invention relates to a resource allocation method for an automatic retransmission request, and relates to a method for allocating a resource by transmitting only a difference in information that can be known through a MAP message received in a previous frame with respect to a sub burst to be retransmitted.

Hereinafter, a brief description will be given of a data retransmission method of a transmitter and a receiver. Wireless communication systems provide high-speed data services using limited resources. For this purpose, an automatic retransmission request scheme is used to efficiently use resources. That is, when the data transmission fails, the receiving side makes a request for retransmission of the corresponding data. In this case, an ARQ (Automatic Repeat Request) method is used as an automatic retransmission technique of data generally used.

The ARQ method informs the sender through an Acknowledgment / Non-Acknowledgment (hereinafter referred to as ACK / NACK) signal as to whether the receiver correctly received the data after receiving the data, and the sender receives the NACK signal. Retransmit the data for the corresponding signal. There are three ARQ schemes: Stop-And-Wait (SAW) ARQ, Go-Back-N (GBN) ARQ, and Selective-Repeat (SR) ARQ.

In the SAW ARQ scheme, the sender waits for receiving an ACK signal or a NACK signal after data transmission. The transmitter transmits new next data when an ACK signal is received, and retransmits previous data when a NACK signal is received. That is, in a manner of transmitting only one frame at a time, after confirming that the frame has been successfully transmitted, the next frame is transmitted.

The GBN ARQ method continuously transmits data regardless of the response message. If the receiver does not receive the data of the specific frame while receiving the data, the receiver cannot transmit the ACK signal of the specific frame to the transmitter. Since the transmitting side does not receive the ACK signal for the specific frame, it retransmits the data of the specific frame.

The SR ARQ method continuously transmits data and then retransmits only data that receives a NACK signal. If the receiving side does not receive data of a specific frame, it transmits a NACK signal to the transmitting side. The transmitting side receiving the NACK signal retransmits the data of the frame indicated by the NACK signal to the receiving side, thereby transmitting all the data. The SR ARQ scheme can be relatively complicated to implement because it needs to assign and manage the sequence number for each frame.

In the method of transmitting data in the form of a packet, a higher data rate is required, and a coding rate or modulation is performed to prevent an error occurring in a high-speed transmission environment. The same method was applied to the communication system. In addition, an ARQ scheme suitable for a high-speed transmission environment, that is, a hybrid ARQ scheme (hereinafter, referred to as HARQ) scheme, has been proposed.

In the ARQ method, when an error occurs, the corresponding information is discarded. However, in the HARQ method, FEC (Forward Error Correction) is applied by storing information in which an error occurs at a receiving side in a buffer and combining the information with retransmission. That is, the HARQ scheme may be regarded as a combination of the FEC and the ARQ scheme. HARQ can be largely classified into the following four ways.

In the first scheme of HARQ, the receiving side always checks an error detection code for data and applies FEC first. The receiver requests retransmission from the sender if there is still an error in the packet. The receiving side discards the packet in error and the transmitting side transmits the same packet using the same FEC code as the discarded packet.

The second scheme of HARQ is called an incremental redundancy (IR) ARQ scheme. In the IR ARQ scheme, the receiving side does not discard the first transmitted packet, but stores it in a buffer and combines the redundancy bits retransmitted. When retransmitting, the transmitting side retransmits only parity bits excluding data bits. The parity bit retransmitted by the transmitting side uses a different one for each retransmission.

The third scheme of HARQ is a special case of the second scheme. Each packet is self-decodable. In the case of retransmission at the transmitting side, the transmitting side reconstructs a packet including both the portion where the error occurs and the data. This method allows more accurate decoding than the second method of the HARQ method, but is less efficient in terms of coding gain.

In the fourth method of HARQ, the function of the first method is added with a function of storing data first received at the receiver and combining the retransmitted data. The fourth type of HARQ scheme is also referred to as a matrix combining scheme or a chase combining scheme. The fourth method of HARQ has a gain in terms of signal to interference noise ratio (SINR), and the parity bits of retransmitted data are always used as the same.

However, the base station transmits the information related to the sub-burst to the terminal through a MAP message in order to support HARQ in the current system. At this time, when there is a lot of HARQ traffic, since the MAP message must be continuously transmitted, a problem that the MAP message overhead becomes large may occur.

In order to support HARQ, which is generally used, the base station transmits information related to automatic retransmission to the terminal through a MAP message. In this case, in the case of a lot of HARQ traffic (transmission), transmitting all information related to automatic retransmission may cause a large overhead. Accordingly, embodiments of the present invention propose a method of transmitting only differences based on MAP information received during initial transmission from a base station. Preferably, only the difference of the location information based on the MAP information can be informed. This can improve the system by reducing the MAP overhead associated with HARQ.

The present invention has been made to solve the above-described problems of the general technique, and an object of the present invention is to propose a method of transmitting only the difference of location information based on MAP information at the time of initial transmission upon retransmission.

Another object of the present invention is to propose a method of reducing MAP overhead associated with HARQ by transmitting only a difference in location information based on MAP information in a previously transmitted MAP message.

In order to solve the above technical problem, the present invention relates to a resource allocation method for an automatic retransmission request.

In one aspect of the present invention, a resource allocation method for an automatic retransmission request includes the steps of transmitting a MAP message including information on whether to support differential allocation; storing MAP information included in the MAP message for a predetermined frame; If the acknowledgment negative message is received during the predetermined frame, the method may include transmitting sub burst information including difference allocation information for a sub burst to be retransmitted.

In addition, in the method, the difference allocation information may include reference frame offset, reference burst number, and reference subband number information according to the number information of the referenced frames to be retransmitted and the number information of the referenced frames.

In this case, the number information of the referenced subburst may be the reference subburst index and the repetitive coding instruction information. In addition, the number information of the referenced subburst may include the reference subburst index and the subburst profile information.

In the method, the MAP message may be one of an SBC message, a DSx message, or a REG message.

Further, in the method, the MAP information may include location information of HARQ subburst.

In another aspect of the present invention, a resource allocation method for an automatic retransmission request includes receiving a MAP message including information on whether to support differential allocation, storing MAP information included in the MAP message for a predetermined frame; If an error occurs in the data packet received during the predetermined frame, transmitting the acknowledgment signal to the base station and sub-burst information including differential allocation information for the sub-burst for retransmitting the data packet from the base station. Receiving may include.

In addition, in the method, the difference allocation information may include reference frame offset, reference burst number, and reference subband number information according to the number information of the referenced frames to be retransmitted and the number information of the referenced frames.

In this case, the number information of the referenced subburst may be the reference subburst index and the repetitive coding instruction information. In addition, the number information of the referenced subburst may include the reference subburst index and the subburst profile information.

The present invention has the following effects.

First, by using the embodiments of the present invention, when the HARQ traffic is heavy, by reducing the MAP overhead associated with HARQ by transmitting only the difference based on the MAP information of the initial MAP message when retransmitting the HARQ subburst. It can improve performance.

Second, when HARQ resource allocation is performed using the differential allocation method proposed in the embodiments of the present invention, the size of the MAP message can be reduced. For example, suppose that 16 subbursts exist in one burst, and 2 subbursts are retransmitted. In this case, in the case of RCID 11, 60 bits per burst are required for the existing retransmitted subburst IE. However, using the differential allocation method requires 32 bits per burst. In addition, the channel environment is poor, and the number of retransmissions increases as the number of terminals in the base station increases. In this case, applying the difference allocation method proposed in the present invention can effectively reduce the size of the MAP message and increase the data rate.

In order to solve the above technical problem, the present invention proposes a resource allocation method for an automatic retransmission request. That is, a method of allocating a resource by transmitting only a difference in information that is known through a MAP message received in a previous frame with respect to the retransmitted subburst will be described.

The following embodiments are a combination of elements and features of the present invention in a predetermined form. Each component or characteristic may be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some of the elements and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments.

Herein, the embodiments of the present invention have been described with reference to the data transmission / reception relationship between the base station and the terminal. Here, the BS has a meaning as a terminal node of a network that directly communicates with the MS. The particular operation described herein as performed by the base station may be performed by an upper node of the base station, as the case may be.

That is, it is apparent that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station can be performed by a network node other than the base station or the base station. A 'base station' may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. The term 'terminal' may be replaced with terms such as User Equipment (UE), Mobile Station (MS), and Mobile Subscriber Station (MSS).

Embodiments of the present invention may be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For a hardware implementation, the method according to embodiments of the present invention may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) , Field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention, and are not intended to limit the scope of the invention.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention;

1 is a diagram illustrating a map structure used in an IEEE 802.16 system.

Currently, the IEEE 802.16 system uses HARQ_DL_MAP_IE and HARQ_UL_MAP_IE as shown in FIG. 1 to support HARQ. In this case, each information element (IE) may allocate several bursts.

Referring to FIG. 1, HARQ_MAP_Pointer_IE may designate a sub burst of DL MAP or UL MAP in downlink. HARQ_DL_MAP_IE may indicate each burst in downlink. In addition, HARQ_UL_MAP_IE may indicate each burst in the uplink.

HARQ_DL_MAP_IE may support HARQ modes such as Chase Combining HARQ, IR HARQ with CTC, and IR HARQ (IR-CC HARQ) for convolutional codes. In chase combining HARQ mode, the burst profile is represented by DIUC. In IR HARQ mode with CTC, the burst profile is indicated by the parameters N _EP and N _SCH . IR-CC HARQ mode is used to indicate non-HARQ transmission.

2 is a diagram illustrating a HARQ downlink allocation structure.

Referring to FIG. 2, one burst may be defined as one or more subburst IEs. Each subburst may have a different concatenation identifier (CID). HARQ_DL_MAP_IE defines one or more two-dimensional data areas. HARQ assignment can be divided into bursts and named lower bursts by assigning a specific number of slots to each burst. All lower bursts in the data area support only one HARQ mode. In this case, the number of slots is indicated by a duration or an N _SCH field. Slots are assigned in order of frequency priority to the slots with the lowest channel number and the lowest channel number starting from the slot with the lowest channel number. Each sub burst can be encoded individually.

For example, in order to allocate HARQ downlink resources, the base station can inform each terminal of the size and location of an area allocated for one sub burst. That is, the first subburst is allocated from the first slot of the HARQ downlink region. The second subburst is allocated from the next slot following the slot assigned to the first subburst. In this way the subbursts can be assigned sequentially. That is, when the UEs receive the HARQ region information and the size of the previous subburst, the UEs can know the slots of the HARQ region allocated thereto.

Each sub burst may have a different burst profile. Therefore, the base station transmits DIUC and Repetition Coding Indication parameter to each terminal in the case of chase combining HARQ and IR-CC HARQ. In addition, the base station transmits N _EP and N _SCH parameters to the terminal in case of IR-CTC HARQ.

In the HARQ mode, one UE may have several HARQ channels and is managed in sub-burst units through each channel. To distinguish between multiple HARQ channels, the base station must transmit an ACID for each subburst. ACID may manage the HARQ channel in sub-burst units. In addition, AI_SN is transmitted to distinguish between initial transmission and retransmission. AI_SN is used to distinguish the ARQ sequence number.

If the HARQ mode of the base station is an IR HARQ mode, the base station should transmit the SPID to the terminal to distinguish between different redundancy versions. The base station may receive an ACK signal for each sub burst. The base station should transmit information on ACK disable to determine whether to receive the ACK. The order of the HARQ ACK channel is determined according to the order of the sub bursts in which the ACK disable is '0' in the MAP. That is, ACK channels are sequentially allocated from the sub bursts having the fastest order in the MAP.

The base station transmits information for each sub burst to support HARQ as follows. The base station transmits connection identifier (CID) information, duration information, burst profile, and control information to the UE. , SPID)) or ACK disable information.

IEEE 802.16 system supports several HARQ modes. In addition to the above-described chain combining HARQ, IR-CC HARQ and IR-CTC HARQ, MIMO chase combining HARQ, MIMO IR-CC HARQ, MIMO IR-CTC HARQ and MIMO STC HARQ modes can be supported.

Different operations are performed in each HARQ mode and parameters transmitted by the base station may also vary. In the case of general chase combining HARQ, the burst profile should always be the same during initial transmission and retransmission, but the slot repetition rate may be different. In addition, the general chase combining HARQ does not need to transmit the SPID for each terminal because the redundancy version is always the same as '00'.

In the case of the IR HARQ mode, the burst profile (eg, Modulation Order, Coding Type, Coding Rate) and the redundancy version may be changed at every transmission. In the IR-CTC HARQ mode, the burst profile may be transmitted through N _EP and N _SCH , and the rest of the HARQ mode may be transmitted through the DIUC and the repetitive coding instruction parameter.

Table 1 below shows an example of the HARQ_DL_MAP_IE format used in downlink.

Syntax Size (bit) Note HARQ_DL_MAP_IE () {  Extended-2 DIUC 4 HARQ_DL_MAP_IE () = 0x07  Length 8 Length in bytes  RCID_Type 2 0b00: Normal CID
0b01: RCID 11
0b10: RCID 7
0b11: RCID 3  Reserved 2  While (data remains)   Boosting 3 0b000: Normal (not boosted)
0b001: + 6dB
0b010: -6dB
0b011: + 9dB
0b100: + 3dB
0b101: -3dB
0b110: -9dB
0b111: -12dB   Region_ID use indicator 1 bit 0: Do not use Region_ID
1: Use Region_ID   If (Region_ID use indicator == 0) {    OFDMA symbol offset 8 Offset from the start symbol of DL subframe    Subchannel offset 7    Number of OFDMA symbols 7    Number of subchannels 7    Rectangular Sub-Burst Indication One Indicates sub-burst allocations are time-first rectangular. The duration field in each sub-burst IE specifies the number of subchannels for each rectangular allocation. This is only valid for AMC allocations and all allocations with dedicated pilots. When this field is clear, sub-bursts shall be allocated in frequeny-first manner and the duration field reverts to the default operation.    reserved 2   } else {   Region_ID 8 Index to the DL region defined in the DL region definition TLV in DCD   }   Mode 4 Indicates the mode of this HARQ region:
0b0000: Chase HARQ
0b0001: Incremental redundancy HARQ for CTC
0b0010: Incremental redundancy HARQ for convolution Code
0b0011: MIMO Chase HARQ
0b0100: MIMO IR HARQ
0b0101: MIMO IR HARQ for Convolutional Code
0b0110: MIMO STC HARQ
0b0111-0b1111: Reserved   Subburst IE Length 8 Length in nibbles, to indicate the size of the subburst IE in this HARQ mode.
The MS may skip DL HARQ. Subburst IE if does not support the HARQ mode. However, the MS shall decode. NACK Channel field from each DL HARQ. Subburst IE to determine the UL ACK channel it shall use for its DL HARQ burst.   If (Mode == 0b0000) {     DL_HARQ_Chase_Sub-Burst_IE () variable   } else if (Mode == 0b0001) {    DL_HARQ_IR_CTC_Sub-Burst_IE () variable   } else if (Mode == 0b0010) {     DL_HARQ_IR_CC_Sub-Burst_IE () variable   } else if (Mode == 0b0011) {  MIMO_DL_Chase_HARQ_IR_HARQ_Sub-Burst_IE () variable   } else if (Mode == 0b0100) {   MIMO_DL_IR_HARQ_Sub-Burst_IE () variable   } else if (Mode == 0b0101) {  MIMO_DL_IR_HARQ_for_CC_Sub-Burst_IE () variable   } else if (Mode == 0b0110) {   MIMO_DL_STC_HARQ_Sub-Burst_IE () variable   }  }  padding variable padding to byte; shall be set to 0 }

HARQ_DL_MAP_IE uses a second extended DIUC. In addition, the base station may use a reduced CID instead of the basic CID or the multicast CID to reduce the size of the HARQ MAP message. The reduced CID type (RCID_Type) is a parameter indicating the type of CID used in HARQ_DL_MAP_IE. Therefore, when RCID_Type indicates '0b00', a normal CID (Normal CID) is used, '0b01' indicates an 11-bit RCID is used, '0b10' indicates a 7-bit RCID is used, and '0b11' May indicate that a 3-bit RCID is used.

The boosting parameter indicates a power boost applied to the data subcarrier when the HARQ MAP message is allocated. The boosting parameter indicates '0b000' when allocating using AMC or PUSC-ASCA permutation in the dedicated pilot region. The magnitude of the power boost allocated to each data subcarrier can be known by referring to the 'boosting' field in Table 1.

If the Region_ID use indicator parameter included in Table 1 indicates '1', it indicates that the Region IDentifier parameter is used. If it indicates '0', it indicates that the region identifier parameter is not used.

If the area identifier parameter is not used, the resource area indicated by HARQ_DL_MAP_IE must be separately indicated. Therefore, the information on the OFDMA symbol offset and the number, the information on the subchannel offset and the number, and the rectangular sub burst indication parameter should be indicated.

If the region identifier parameter is used, the region identifier indicates a downlink resource region defined for the downlink channel in a downlink channel descriptor (DCD) message.

In Table 1, the Mode field indicates a mode of HARQ. Therefore, if the mode field indicates '0b0000', the chase HARQ mode is indicated, '0b0001' indicates the CTC-IR HARQ mode, '0b0010' indicates the CC-IR HARQ mode, '0b0011' indicates the MIMO chase HARQ mode, and '0b0100'. 'May indicate the MIMO IR HARQ mode,' 0b0101 'may indicate the MIMO CC-IR HARQ mode, and' 0b0110 'may indicate the MIMO STC HARQ mode. At this time, '0b0111 to 0b1111' indicates a field reserved for another HARQ mode.

In Table 1, the Subburst IE Length parameter indicates the length of the subburst in the corresponding HARQ mode. If the terminal does not support the HARQ mode used by the base station, the terminal may ignore the DL HARQ subburst transmitted in the corresponding HARQ mode. However, each terminal must decode the NACK channel field in the DL-HARQ subburst IE to determine the uplink ACK channel.

Table 2 below shows an example of a sub burst format of the downlink chase HARQ.

Syntax Size (bit) Notes DL_HARQ_Chase_Sub-Burst_IE () {  N sub burst [ISI] 4 Number of sub-bursts in the 2D rectangular region is this field value plus 1.  N ACK channel 4 Number of HARQ ACK enabled subbursts in the 2D region.  For (j = 0; j <Number of sub-bursts; j ++) {   RCID_IE () variable   Duration 10 Duration in slots   Sub-Burst DIUC Indicator One If Sub-Burst DIUC Indicator is 1, it indicates that DIUC is explicitly assigned for this subburst. Otherwise, the this subburst will use the same DIUC as the previous subburst If j is 0 then this indicator shall be 1.   Reserved One Shall be set to zero.   If (Sub-Burst DIUC Indicator == 1) {    DIUC 4    Repetition Coding Indication 2 0b00: No repetition coding
0b01: Repetition coding of 2 used
0b10: Repetition coding of 4 used
0b11: Repetition coding of 6 used    Reserved 2 Shall be set to zero.   }   ACID 4   AI_SN One   ACK disable One When ACK Disable == 1, the allocated subburst does not require an ACK to be transmitted by the SS in the ACKCH Region (see 8.4.5.4.25). In this case, no ACK channel is allocated for the subburst in the ACKCH Region. For the burst, BS shall not perform HARQ retransmission and MS shall ignore ACID, AI_SN and SPID, which shall be set to 0 by BS if they exist.   Dedicated DL Control Indicator 2 LSB # 0 indicates inclusion of CQI control LSB # 1 indicates inclusion of Dedicated DL Control IE.  If (LSB # 0 of Dedicated DL Control Indicator == 1) {    Duration (d) 4 A CQI feedback is transmitted on the CQI chan-nels indexed by the (CQI Channel Index) by the SS for 2 ^(d-1) frames. If d is 0b0000, deallocates all CQI feedback when the current ACID is com-pleted successfully. If d is 0b1111, the MS should report until the BS command for the MS to stop.    If (Duration! = 0b0000) {      Allocation Index 6 Index to the channel in a frame the CQI report should be transmitted by the SS.      Period (p) 3 A CQI feedback is transmitted on the CQI chan-nels indexed by the (CQI Channel Index) by the SS in every 2p frames.      Frame offset 3 The MS starts reporting at the frame of which the number has the same 3 LSB as the specified frame offset. If the current frame is specified, the MS should start reporting in eight frames.    }   }  If (LSB # 1 of Dedicated DL Control Indicator == 1) {    Dedicated DL Control IE () variable   }  } }

DL_HARQ_Chase_Sub-Burst_IE of Table 2 may be included in the HARQ MAP message of Table 1. That is, in Table 1, the HARQ mode used in the base station when the mode field indicates '0b0000' is a chase HARQ mode.

Referring to Table 2, the 'N sub burst [ISI]' field indicates the number of subbursts in the 2D rectangular area. 'N ACK channel' represents the number of sub-bursts that can be allocated for HARQ ACK transmission in a two-dimensional region.

The size of radio resources allocated to Table 2 increases with the number of subbursts.

The reduced CID (RCID_IE) indicates the type of RCID used at the base station. The Duration parameter indicates the valid duration of a slot per subburst. A Sub-Burst DIUC Indicator field value of '1' indicates that the DIUC is explicitly assigned to the subburst, and a '0' indicates that the subburst uses the same DIUC as the previous subburst. .

When the subburst DIUC indicator field indicates '1', the DIUC is allocated for each subburst, and the Repetiton Coding Indication field indicates the repetitive coding used for the assigned burst. That is, if the repetition coding instruction field is '0b00', coding is not repeated, '0b01' is used for repetitive coding twice, '0b10' is used for repetitive coding four times, and '0b11' is used for repetitive coding. Repetitive coding is used six times.

The 'ACID' field is used to manage the HARQ channel and is given in subburst units. The 'AI_SN' field is for distinguishing between initial transmission and retransmission, and through this, an ARQ sequence number can be distinguished. If the 'ACK disable' field indicates 1, the allocated sub burst does not require an ACK signal transmitted by the terminal in the allocated ACK region. In this case no ACK channel is assigned to the subburst in the ACK region. The base station does not perform HARQ retransmission for the burst, and the terminal ignores the 'ACID', 'AI_SN' and 'SIPD' parameters.

The LSB # 0 bit of the dedicated DL Control Indicator parameter indicates whether CQI control is included and the LSB # 1 bit indicates whether or not the dedicated downlink control indicator is included.

If the LSB # 0 bit of the dedicated downlink control indicator indicates 1, CQI feedback is transmitted through a channel indexed with a CQI channel index every 2 ^(d-1) frames.

If the duration field is not '0b0000', an allocation index parameter indicates an index of a channel to which a CQI report is transmitted by the terminal in a frame. Also,

CQI feedback is sent on CQI channels indexed by the CQI channel index every 2 ^P frames. In this case, the period parameter indicates a transmission period p of the CQI feedback.

The UE starts reporting on the same number of frames as three LSBs at a specific frame offset. In this case, the frame offset parameter informs the time point at which the terminal reports. If the current frame is a specific frame, the terminal starts transmission in eight frames.

 Table 3 below shows an example of a downlink CTC-IR HARQ subburst format.

construction( Syntax ) size( bit ) Contents( Notes ) DL_HARQ_IR_CTC_Sub-Burst_IE () {   N sub burst [ISI] 4 Number of sub-bursts in the 2D rectangular region is this field value plus 1.   N ACK channel 4 Number of HARQ ACK enabled subbursts in the 2D region.   For (j = 0; j <Number of sub-bursts; j ++) {    RCID_IE () variable N _EP 4 N _SCH 4 SPID 2    ACID 4    AI_SN One    ACK disable One When ACK Disable == 1, the allocated subburst does not require an ACK to be transmitted by the SS in the ACKCH Region (see 8.4.5.4.25). In this case, no ACK channel is allocated for the subburst in the ACKCH Region. For the burst, BS shall not perform HARQ retransmission and MS shall ignore ACID, AI_SN and SPID, which shall be set to 0 by BS if they exist.    Reserved 2 Shall be set to zero.    Dedicated DL Control Indicator 2 LSB # 0 indicates inclusion of CQI control LSB # 1 indicates inclusion of Dedicated DL Control IE.  If (LSB # 0 of Dedicated DL Control Indicator == 1) {     Duration (d) 4 A CQI feedback is transmitted on the CQI chan-nels indexed by the (CQI Channel Index) by the SS for 2 ^(d-1) frames. If d is 0b0000, deallocates all CQI feedback when the current ACID is com-pleted successfully. If d is 0b1111, the MS should report until the BS command for the MS to stop.    If (Duration! = 0b0000) {      Allocation Index 6 Index to the channel in a frame the CQI report should be transmitted by the SS.      Period (p) 3 A CQI feedback is transmitted on the CQI chan-nels indexed by the (CQI Channel Index) by the SS in every 2p frames.      Frame offset 3 The MS starts reporting at the frame of which the number has the same 3 LSB as the specified frame offset. If the current frame is specified, the MS should start reporting in eight frames.     }    }  If (LSB # 1 of Dedicated DL Control Indicator == 1) {     Dedicated DL Control IE () variable    }   } }

DL_HARQ_IR_CTC_Sub-Burst_IE of Table 3 may be included in the HARQ MAP message of Table 1. That is, in Table 1, the HARQ mode used in the base station when the mode field indicates '0b0001' is an IR-CTC HARQ mode.

Referring to Table 3, the 'N sub burst [ISI]' field indicates the number of subbursts in the 2D rectangular area. 'N ACK channel' represents the number of possible subbursts of HARQ ACK in the two-dimensional region.

The size of radio resources allocated to Table 3 increases with the number of subbursts. In Table 3, the reduced CID (RCID_IE) parameter indicates the type of RCID allocated to each terminal. The N _EP and N _SCH parameters indicate the burst profile of the IR-CTC HARQ. In addition, the SPID parameter represents a service flow identifier, and the ACID parameter is allocated in units of subbursts. That is, an ACID parameter is used for each subburst to manage multiple HARQ channels. The AI_SN parameter is used to distinguish between initial transmission and retransmission.

If the 'ACK disable' field indicates 1, the allocated sub burst does not require an ACK signal transmitted by the terminal in the allocated ACK region. In this case no ACK channel is assigned to the subburst in the ACK region. The base station does not perform HARQ retransmission for the burst, and the terminal ignores the 'ACID', 'AI_SN' and 'SIPD' parameters. In this case, the CRC may be added to the end of each sub burst regardless of the ACK disable bit.

The LSB # 0 bit of the dedicated DL Control Indicator parameter indicates whether CQI control is included and the LSB # 1 bit indicates whether or not the dedicated downlink control indicator is included.

If the LSB # 0 bit of the dedicated downlink control indicator indicates 1, CQI feedback is transmitted through a channel indexed with a CQI channel index every 2 ^(d-1) frames.

If the duration field is not '0b0000', an allocation index parameter indicates an index of a channel to which a CQI report is transmitted by the terminal in a frame. At this time, CQI feedback is transmitted on CQI channels indexed by the CQI channel index every 2 ^P frames. In this case, the period parameter indicates a transmission period p of the CQI feedback.

The UE starts reporting on the same number of frames as three LSBs at a specific frame offset. In this case, the frame offset parameter informs the time point at which the terminal reports. If the current frame is a specific frame, the terminal starts transmission within 8 frames.

In order to support HARQ, which is generally used, the base station transmits information related to automatic retransmission to the terminal through a MAP message. In this case, in the case of a lot of HARQ traffic (transmission), transmitting all information related to automatic retransmission may cause a large overhead. Accordingly, embodiments of the present invention propose a method of transmitting only differences based on MAP information received during initial transmission from a base station. This can improve the system by reducing the MAP overhead associated with HARQ.

FIG. 3 is a diagram illustrating a method of transmitting only a difference between information required for retransmission from information known through a MAP message received in a previous frame according to an embodiment of the present invention.

One embodiment of the present invention relates to a resource allocation method for a packet retransmitted to a terminal. The method proposed in the present invention will be referred to as a differential allocation method.

Referring to FIG. 3, the base station transmits a MAP message including a MAP IE to one or more terminals included in its cell area (S301).

In step S301, the MAP message includes an SBC message, a DSx message, or a REG message. In addition, the MAP message may include information indicating whether to use the difference allocation method and transmit the information to the terminals.

The base station stores information related to retransmission (MAP information) included in the MAP IE transmitted by the base station for a predetermined frame. In this case, the MAP information may include location information of subbursts to be retransmitted (S302).

In step S302, it is assumed that a predetermined frame is n frames. The predetermined number of frames can be changed according to the communication environment between the terminal and the base station or the requirements of the user. The terminal that receives the MAP IE from the base station in step S302 may also store information related to retransmission included in the MAP IE for n frames.

The base station and the terminal may store the MAP information for n frames. At this time, the base station monitors whether the NACK signal is received from the terminal for n frames (S303).

If the base station receives the NACK signal from the terminal in n frames in step S303 (S304), the base station can identify the burst and subframe to be retransmitted for the NACK signal (S305).

Since the base station stores the location information of the sub-bursts for retransmission included in the MAP information for n frames, the base station can select and transmit only the information necessary for retransmission, not all MAP IE to the terminal (S306).

That is, only the sub-burst IE necessary for retransmission in step S306 is selected and transmitted to the terminal. At this time, a differential allocation method may be used.

If the NACK signal is not received for n frames, the base station may transmit another MAP IE for HARQ to the terminal (S307).

4 is a diagram illustrating a method of performing HARQ using a differential allocation method between a base station and a terminal according to an embodiment of the present invention.

When the base station and the terminal communicates using HARQ, the base station may transmit a parameter related to HARQ to the terminal using MAP messages. In this case, the MAP message includes an SBC message, a DSx message, and a MAC management message, which are used to negotiate basic capabilities between the terminal and the base station, and a REG message. In addition, the base station may include differential allocation usage information in the MAP message and transmit it to the terminal (S401).

In the embodiment of the present invention, it is assumed that the difference allocation method is used. Accordingly, the base station and the terminal store the MAP information of the current frame, and stores the MAP information for a predetermined frame. In an embodiment of the present invention, the predetermined frame may be 16 frames. Of course, the number of frames may be determined according to the requirements of the system environment or the user.

At this time, the base station and the terminal may store the MAP information of the current frame, and then maintain the MAP information for 16 frames. Accordingly, the base station and the terminal may have MAP information for up to 16 frames in a specific frame.

In the process of transmitting and receiving the data packet between the base station and the terminal, if an error occurs in the data packet transmitted by the base station, the terminal may transmit a NACK signal to the base station (S402).

Since the base station has received the NACK signal within 16 frames after transmitting the MAP message, the base station can check from the stored MAP information on which previous frame the subframe to be retransmitted has been allocated. In this case, a specific number of frames for which the largest number of subbursts are retransmitted may be selected. In addition, the base station may check the order of the burst including the subframe to be retransmitted for the selected frame and the order of the subframe in the burst (S403).

The base station may select the sub-burst allocation information for the packet indicated by the NACK signal from the stored MAP information and transmit it to the terminal. In this case, the base station may inform the terminal of the location of the packet to be retransmitted using a differential allocation method. That is, the base station may transmit a sub-burst IE including the difference allocation information to the terminal (S404).

In step S404, the base station may transmit to the terminal a sub-burst IE including information on the allocation position previously transmitted and a Repetition Coding Indication parameter of the sub-burst to be retransmitted, to transmit the packet to be retransmitted to the terminal. have.

In operation S404, the difference allocation information included in the sub burst IE may include a frame reference parameter and a frame offset parameter indicating the number of frames in which the sub burst to be retransmitted is transmitted. In addition, the difference allocation information includes the number of bursts (Reference Burst number) according to the frame offset parameter, information indicating the number of sub-bursts (N reference sub-burst), and information indicating the index of the sub-burst (Reference Sub-Burst index). It may be further included.

The differential allocation method can be applied to various HARQ modes. According to an embodiment of the present invention, a case in which the differential allocation method is applied to the chase combining HARQ mode and the IR-CTC HARQ mode will be considered. Of course, it can be applied to other HARQ methods according to the communication environment or user requirements. Hereinafter, examples of the sub-burst IE format that can be used in step S404 will be described with Tables 4 and 5.

Table 4 below shows an example of a sub-burst IE format including difference allocation information in the chase combining HARQ to which the difference allocation method is applied.

Syntax Size (bit) Notes Diff_DL_HARQ_Chase_Sub-Burst_IE () {  N sub burst [ISI] 4 Number of sub-bursts in the 2D rectangular region is this field value plus 1.  N ACK channel 4 Number of HARQ ACK enabled subbursts in the 2D region.  For (j = 0; j <Number of sub-bursts; j ++) {   RCID_IE () variable   Duration 10 Duration in slots   Sub-Burst DIUC Indicator One If Sub-Burst DIUC Indicator is 1, it indicates that DIUC is explicitly assigned for this subburst. Otherwise, the this sub burst will use the same DIUC as the previous subburst If j is 0 then this indicator shall be 1. Reserved One Shall be set to zero.   If (Sub-Burst DIUC Indicator == 1) {     DIUC 4     Repetition Coding Indication 2 0b00: No repetition coding
0b01: Repetition coding of 2 used 0b10: Repetition coding of 4 used 0b11: Repetition coding of 6 used Reserved 2 Shall be set to zero.   }   ACID 4   AI_SN One   ACK disable One When ACK Disable == 1, the allocated sub burst does not require an ACK to be transmitted by the SS in the ACK CH Region (see 8.4.5.4.25). In this case, no ACK channel is allocated for the subburst in the ACK CH Region. For the burst, BS shall not perform HARQ retransmission and MS shall ignore ACID, AI_SN and SPID, which shall be set to 0 by BS if they exist.   Dedicated DL Control Indicator 2 LSB # 0 indicates inclusion of CQI control LSB # 1 indicates inclusion of Dedicated DL Control IE.  If (LSB # 0 of Dedicated DL Control Indicator == 1) {     Duration (d) 4 A CQI feedback is transmitted on the CQI chan-nels indexed by the (CQI Channel Index) by the SS for 2 ^(d-1) frames. If d is 0b0000, deallocates all CQI feedback when the current ACID is com-pleted successfully. If d is 0b1111, the MS should report until the BS command for the MS to stop.     If (Duration! = 0b0000) {       Allocation Index 6 Index to the channel in a frame the CQI report should be transmitted by the SS.       Period (p) 3 A CQI feedback is transmitted on the CQI chan-nels indexed by the (CQI Channel Index) by the SS in every 2p frames.       Frame offset 3 The MS starts reporting at the frame of which the number has the same 3 LSB as the specified frame offset. If the current frame is specified, the MS should start reporting in eight frames.     }    }  If (LSB # 1 of Dedicated DL Control Indicator == 1) {       Dedicated DL Control IE () variable    }   } Differential allocation Indicator One If Differential allocation Indicator is 1, it indicates inclusion of differential allocation. reserved 3 Shall be set to zero. if ( Differential allocation Indicator == 1) {     N frame reference 4 Number of frame to be referenced by this IE. for (i = 0; i <N frame reference ; i ++) { Reference Frame offset 4 Offset in frames with respect to this frame. This offset should be larger than 1. Reference Burst number 4 Burst number in frame defined by frame offset      N reference sub - burst 4 indicate sub-burst number to be referenced for (k = 0; k <N reference sub - burst ; k ++) { Reference Sub - Burst index 4 indicate sub-burst position in the Burst defined by Reference Burst number and Reference Frame offset Repetition Coding Indication 4 reserved 2 Shall be set to zero.      }     }   } }

Table 4 is basically similar to Table 2. However, Table 4 is a subburst (Diff_DL_HARQ_Chase_Sub-Burst_IE) format to which a differential allocation method is applied. Therefore, only the information added for the difference allocation method will be described. For descriptions of other parameters, refer to the description of Table 2.

Referring to Table 4, when the differential allocation indicator parameter indicates '1', it may indicate that a differential allocation method is applied. In this case, the N frame reference may indicate the number of frames in which the sub burst of the packet to be retransmitted is. According to the number of frame reference parameters, a frame offset reference parameter indicates reference information of a corresponding frame. In this case, the reference burst number parameter indicates the number of bursts in the frame defined by the frame offset. In addition, the N reference sub-burst parameter may indicate the number of referenced sub bursts.

According to the number of subbursts, the Reference Sub-Burst index parameter indicates the position of the subbursts. In this case, the position of the sub burst may be defined by a reference burst number parameter and a reference frame offset parameter. In addition, the coding rate may be different for each sub burst. Therefore, a Repetition Coding Indication parameter should be informed for each sub burst.

Table 5 below shows an example of a sub-burst IE format including differential allocation information in IR-CTC HARQ to which a differential allocation method is applied.

Syntax Size (bit) Notes Diff_DL_HARQ_IR_CTC_Sub-Burst_IE () {  N sub burst [ISI] 4 Number of sub-bursts in the 2D rectangular region is this field value plus 1.  N ACK channel 4 Number of HARQ ACK enabled subbursts in the 2D region.  For (j = 0; j <Number of sub-bursts; j ++) {   RCID_IE () variable N _EP 4 N _SCH 4 SPID 2   ACID 4   AI_SN One   ACK disable One When ACK Disable == 1, the allocated subburst does not require an ACK to be transmitted by the SS in the ACKCH Region (see 8.4.5.4.25). In this case, no ACK channel is allocated for the subburst in the ACKCH Region. For the burst, BS shall not perform HARQ retransmission and MS shall ignore ACID, AI_SN and SPID, which shall be set to 0 by BS if they exist. Reserved 2 Shall be set to zero.   Dedicated DL Control Indicator 2 LSB # 0 indicates inclusion of CQI control LSB # 1 indicates inclusion of Dedicated DL Control IE.  If (LSB # 0 of Dedicated DL Control Indicator == 1) {     Duration (d) 4 A CQI feedback is transmitted on the CQI chan-nels indexed by the (CQI Channel Index) by the SS for 2 ^(d-1) frames. If d is 0b0000, deallocates all CQI feedback when the current ACID is com-pleted successfully. If d is 0b1111, the MS should report until the BS command for the MS to stop.     If (Duration! = 0b0000) {      Allocation Index 6 Index to the channel in a frame the CQI report should be transmitted by the SS.      Period (p) 3 A CQI feedback is transmitted on the CQI chan-nels indexed by the (CQI Channel Index) by the SS in every 2p frames.      Frame offset 3 The MS starts reporting at the frame of which the number has the same 3 LSB as the specified frame offset. If the current frame is specified, the MS should start reporting in eight frames.     }   }  If (LSB # 1 of Dedicated DL Control Indicator == 1) {   Dedicated DL Control IE () variable   }  } Differential allocation Indicator One If Differential allocation Indicator is 1, it indicates inclusion of differential allocation. reserved 3 Shall be set to zero.  if (Differential allocation Indicator == 1) {    N frame reference 4 Number of frame to be referenced by this IE.    for (i = 0; i <N frame reference; i ++) { Reference Frame offset 4 Offset in frames with respect to this frame. This offset should be larger than 1. Reference Burst number 4 Burst number in frame defined by frame offset     N reference sub - burst 4 indicate sub-burst number to be referenced     for (k = 0; k <N reference sub-burst; k ++) { Reference Sub - Burst index 4 indicate sub-burst position in the Burst defined by Reference Burst number and Reference Frame offset N _EP 4 N _SCH 4 SPID 2 reserved 2 Shall be set to zero.     }    }   } }

Table 5 is basically similar to Table 3. However, Table 5 is an example of a sub burst (Diff_DL_HARQ_IR_CTC_Sub-Burst_IE) format to which a differential allocation method is applied. Therefore, only the information added for the difference allocation method will be described. For descriptions of other parameters, refer to the description of Table 3.

Referring to Table 5, when the differential allocation indicator parameter indicates '1', it may indicate that the differential allocation method is applied to the HARQ mode. Therefore, a parameter indicating difference allocation information will be described below. The N frame reference may indicate the number of frames in which the sub burst of the packet to be retransmitted is. According to the number of frame reference parameters, a frame offset reference parameter indicates reference information of a corresponding frame. In this case, the reference burst number parameter indicates the number of bursts in the frame defined by the frame offset. In addition, the N reference sub-burst parameter may indicate the number of referenced sub bursts.

According to the number of subbursts, the Reference Sub-Burst index parameter indicates the position of the subbursts. In this case, the position of the sub burst may be defined by a reference burst number parameter and a reference frame offset parameter.

In the case of the IR-CTC HARQ mode, a burst profile (for example, Modulation Order, Coding Type, or Coding Rate) and a redundancy version may be changed at every transmission for each UE. Therefore, the burst profile can be informed to the terminals using N _EP and N _SCH parameters. In addition, the service flow identifier (SPID) parameter may be further included in the sub burst IE to identify each service and transmitted to the terminals.

Referring back to FIG. 4, when the sub-burst IEs shown in Tables 4 and 5 are transmitted to the terminal in step S404 of FIG. 4, the terminal may extract decoding information by using differential allocation information (S405).

In step S405, the terminal may extract decoding information of the retransmitted packet using the stored MAP information and the differential allocation information included in the sub burst IE received from the base station. That is, the terminal can extract the decoding information of the retransmitted packet by tracking the packet in the order of the frame, burst, sub-burst from the stored MAP information. The terminal may decode the packet through the information extracted from the MAP information of the previous frame and the burst profile transmitted in the MAP of the current frame.

In Table 4 and Table 5, the difference allocation method was applied to the chase combining HARQ mode and the IR-CTC HARQ mode. However, the differential allocation method may be applied to other HARQ modes. For example, the new sub burst IE can be added to HARQ_DL_MAP_IE by selecting a mode from '0b0111' to '0b1111'. The subburst IE may be configured in the same manner as described in Tables 4 and 5 with respect to another HARQ mode of downlink and an uplink HARQ mode.

Referring to FIG. 4, the terminal stores the MAP information received in step S401 for a predetermined frame (for example, 16 frames), and is currently stored in the MAP information stored through the sub burst IE to which the difference allocation method received in step S404 is applied. The location including the decoding information of the packet to be retransmitted can be checked. Accordingly, the terminal may extract decoding information of the retransmission packet by using the MAP information and the difference allocation information.

5 is a diagram illustrating an example of a resource allocation method for a packet retransmitted to a terminal using a differential allocation method according to an embodiment of the present invention.

Referring to FIG. 5, packets to be retransmitted occur in the tenth and eleventh frames (FNs). Therefore, the base station can inform the terminal of the location including the decoding information of the packet to be retransmitted using the difference allocation method described in FIG. Accordingly, the base station may allocate an HARQ subburst for the retransmission packet in the fifteenth frame.

FIG. 6 is a diagram illustrating how resources are allocated by using a subburst IE defined in an embodiment of the present invention.

6 shows a portion of a burst. In FIG. 6, the front region of the burst may sequentially allocate subbursts for initial transmission or retransmission, as defined in the existing subburst IE. The rear region of the burst may only assign subbursts that are retransmitted as defined in the subburst IE using the differential allocation method. In this case, the burst area for the retransmitted subburst is an area enclosed by a dotted line. In addition, when the difference allocation method is applied, the allocation of the ACK channel may be allocated according to the burst order in the current MAP region.

FIG. 7 is a diagram for a method of performing HARQ using a differential allocation method between a base station and a terminal according to another embodiment of the present invention.

7 illustrates a case where one or more terminals exist in a cell area of a base station. That is, the system may be composed of a base station (BS), the first terminal (MS # 1) and the second terminal (MS # 2).

Referring to FIG. 7, when the base station BS and the terminals MS # 1 and MS # 2 communicate using HARQ, the base station may transmit parameters related to HARQ to the terminals using MAP messages. have. In this case, the MAP message includes an SBC message, a DSx message, and a MAC management message, which are used to negotiate basic capabilities between the terminal and the base station, and a REG message. In addition, the base station may include information on whether the differential allocation is used in the MAP message and transmit the information to the terminals (S701 and S702).

In the embodiment of the present invention, it is assumed that the difference allocation method is used. Accordingly, the base station and the terminal may store the MAP information of the current frame and store the MAP information for a predetermined frame. In an embodiment of the present invention, the predetermined frame may be 16 frames. Of course, the number of frames may be determined according to the requirements of the system environment or the user.

In the case of using the differential allocation method in FIG. 7, the base station and the terminal may store MAP information of the current frame and maintain it for 16 frames. Therefore, the base station and the terminal may have MAP information for up to 16 frames in a specific frame.

In the process of transmitting and receiving the data packet between the base station and the terminal, an error may occur in the data packet transmitted by the base station. In another embodiment of the present invention, it is assumed that an error does not occur in the data packet in the first terminal MS # 1, but an error occurs in the data packet in the second terminal MS # 2. Accordingly, the second terminal MS # 2 may transmit a NACK signal to the base station (S703).

Since the base station has received the NACK signal within 16 frames after transmitting the MAP message, the base station can confirm through the MAP information storing the information on the subframe to be retransmitted. In this case, the base station may select a specific number of frames for which the largest number of subbursts are retransmitted. In addition, the base station may check the order of the bursts including the subframes to be retransmitted for the selected frame and the order of the subframes in the corresponding bursts (S704).

The base station may select the sub-burst allocation information for the packet indicated by the NACK signal from the stored MAP information and transmit it to the terminal. In this case, the base station may inform the second terminal of the location of the packet to be retransmitted using a difference allocation method. That is, the base station may transmit the sub-burst IE including the differential allocation information to the second terminal (S705).

In step S705, the base station transmits a second sub-burst IE including information on an allocation position previously transmitted and a repetition coding instruction parameter of a sub-burst to be retransmitted, in order to transmit a packet to be retransmitted to the second terminal. It can transmit to the terminal.

In operation S705, the difference allocation information included in the sub burst IE may include a frame reference parameter and a frame reference parameter indicating the number of frames. In addition, the difference allocation information includes the number of bursts (Reference Burst number) according to the frame offset parameter, information indicating the number of sub-bursts to be retransmitted (N reference sub-burst), and information indicating the index of the sub-burst (Reference Sub -Burst index) may be further included.

At this time, the sub bursts IE to which the differential allocation method is applied in step S705 may use the sub burst IEs defined in Tables 4 and 5. In addition, the differential allocation method may be applied to various HARQ modes. In another embodiment of the present invention, the case where the differential allocation method is applied to the chase combining HARQ mode and the IR-CTC HARQ mode has been examined. However, the differential allocation method may be applied to other HARQ methods according to a communication environment or user requirements.

Referring to FIG. 7, when the sub-burst IE described in Tables 4 and 5 is transmitted to the second terminal in step S705, the second terminal decodes the packet to be retransmitted using the difference allocation information included in the sub-burst IE. It may be extracted (S706).

In operation S706, the second terminal may extract decoding information of the retransmitted packet using the stored MAP information and the differential allocation information included in the sub burst IE received from the base station. That is, the second terminal can extract the decoding information of the retransmitted packet by tracking the packet in the order of the frame, burst, sub-burst from the stored MAP information. The second terminal may decode the packet through the information extracted from the MAP information of the previous frame and the burst profile transmitted from the MAP information of the current frame.

When a predetermined frame elapses, the base station may transmit a message including new MAP information to all terminals included in its cell area (S707 and S708). In addition, in the subsequent process, the HARQ subburst may be allocated by applying a differential allocation method.

Persistent allocation for Voice over Internet Protocol (VoIP), which is currently discussed in the WiMAX forum, allows resources to be allocated periodically over multiple frames by sending one IE for initial transmission. When the frame offset value is '0' to support the persistent allocation, the terminal may recognize this as a retransmission of the packet allocated by the persistent allocation. Therefore, when the embodiments of the present invention are applied to VoIP, by transmitting a packet position in the persistent allocation IE (Persistent Allocation IE) to the terminal, it is possible to apply a differential allocation method for retransmission even in the case of VoIP.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention. In addition, claims that do not have an explicit citation in the claims may be combined to form an embodiment or included in a new claim by amendment after the application.

1 is a diagram illustrating a map structure used in an IEEE 802.16 system.

2 is a diagram illustrating a HARQ downlink allocation structure.

FIG. 3 is a diagram illustrating a method of transmitting only a difference between information required for retransmission from information known through a MAP message received in a previous frame according to an embodiment of the present invention.

4 is a diagram illustrating a method of performing HARQ using a differential allocation method between a base station and a terminal according to an embodiment of the present invention.

5 is a diagram illustrating an example of a resource allocation method for a packet retransmitted to a terminal using a differential allocation method according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating how resources are allocated by using a subburst IE defined in an embodiment of the present invention.

FIG. 7 is a diagram for a method of performing HARQ using a differential allocation method between a base station and a terminal according to another embodiment of the present invention.

Claims (10)

In the resource allocation method for automatic retransmission request, Transmitting a MAP message including information on whether to support differential allocation; Storing MAP information included in the MAP message for a predetermined frame; And And when receiving an acknowledgment negative message during the predetermined frame, transmitting subburst information including differential allocation information for the subburst to be retransmitted. The method according to claim 1, The difference allocation information, And reference frame offset, reference burst number, and reference sub burst number information according to the number information of the referenced frames to be retransmitted and the number information of the referenced frames. 3. The method of claim 2, The number information of the referenced sub bursts is And the reference subburst index and repetitive coding instruction information. 3. The method of claim 2, The number information of the referenced sub bursts is And the reference subburst index and the subburst profile information. The method according to claim 1, The MAP message is, Resource allocation method, characterized in that one of the SBC message, DSx message or REG message. The method according to claim 1, The MAP information, Resource allocation method comprising the position information of the HARQ sub-burst. In the resource allocation method for automatic retransmission request, Receiving a MAP message including information on whether to support differential allocation; Storing MAP information included in the MAP message for a predetermined frame; Transmitting an acknowledgment signal to the base station when an error occurs in the data packet received during the predetermined frame; And And receiving subburst information including differential allocation information for a subburst for retransmitting the data packet from the base station. 8. The method of claim 7, The difference allocation information, And reference frame offset, reference burst number, and reference sub burst number information according to the number information of the referenced frames to be retransmitted and the number information of the referenced frames. 9. The method of claim 8, The number information of the referenced sub bursts is And the reference subburst index and repetitive coding instruction information. 9. The method of claim 8, The number information of the referenced sub bursts is And the reference subburst index and the subburst profile information.

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